The vulnerability is a Java-based vulnerability in QuickTime, which is installed by default on Mac OS X. Any Java-enabled Web browser on this platform is an attack vector and at this point, both Safari and FireFox have been confirmed to be vulnerable. This vulnerability may not only affect Mac OS, FireFox on Windows is also considered at risk at this time.

To protect yourself, turn off all unnecessary browser features such as extra plug-ins, JavaScript and Java.